The invention is concerned with a textile floor covering consisting of a textile layer, to the carrier layer of which the surface material (pile) is applied, a bottom of thermoplastic foam and, if necessary, of additional layers, and a process for its manufacture. It is known to provide textile floor coverings on their bottom side with thermoplastic layers.
Thus it is known to apply dispersions or solutions of thermoplastics to the bottom side of textile layers and to remove the solvents or dispersing agents afterwards. Doing so a foaming, if required, can be performed in one operation. The bottom side of these carpets or floor coverings is then provided with a flexible covering which can, if necessary, be foamed. The plastic foam can be provided with an embossing to render it non-skid. Furthermore it is known to glue thermoplastic sheetings on the bottom side of textile floor coverings. However, with this technology unsatisfactory results were achieved due to the bad binding property of thermoplastics. Finally it is known to provide the bottom side of the textile covering with a plastisol, to melt the applied plastisol compound and to combine it with a thermoplastic sheeting, which can be a foamed sheeting. In order to prevent a destruction of the foam structure, the foamed sheeting is applied in cold state. The heat contained in the plastisol melt must be adequate for joining the layers. This process has the disadvantages that in each case several operations are required, that the removal of the dispersing agent or the solvent necessitates higher technological expenses and that according to these processes only such thermoplastics can be used as do not possess optimum mechanical properties or a high permanent weight, such as polyvinyl chloride.
Subject of the invention is a textile floor covering having a high step elasticity, a high restoring property, a high mechanical strength as well as dust and water impermeability and which can be manufactured by means of a simple technology saving the otherwise usual operations.
This problem is solved by means of a textile floor covering consisting of a textile layer, to the carrier layer of which the pile has been applied, a bottom of thermoplastic foam and, if necessary, additional layers, in which according to the invention the textile layer is directly combined with a foamed sheeting of polymerizates of the ethylene as a bottom.
The bottom can consist of a foamed sheeting of homopolymerizates of the ethylene or of copolymerizates of the ethylene, preferably of ethylene-vinylacetate copolymerizate. Foamed sheetings of mixtures of ethylene homopolymerizates and ethylene copolymerizates, preferably ethylene-vinylacetate copolymers, can also very well be used.
The foamed sheeting has a thickness of 1.5 to 10 mm and a density of 0.10 to 0.40 g/cm.sup.3, preferably 0.15 to 0.20 g/cm.sup.3. It has an open or preferably closed foam structure at the surface and a closed or mixed cells foam structure inside. The connection of the carrier layer with the pile can be achieved by sewing, knitting, stitch-bonding or needling. The pile consists preferably of polyamide, polyacrylonitrile, rayon silk, polyester, polyolefin fibres, wool or animal hair. The carrier layer can consist of natural or synthetic fibres or of glass fibres.
The textile floor covering according to the invention can consist of carpets in fixed sizes, carpet lengths or carpet tiles.
The textile layer can be directly connected with the foamed sheeting of polymerizates as a bottom by means of a cooled melt of a polymerizate. The cooled melt should consist of the same polymerizate as the foamed sheeting. Preferably this cooled melt consists of ethylene-vinyl-acetate copolymerizates.
The textile floor coverings according to the invention are manufactured in such a way that a textile layer is directly applied to a foamed sheeting of ethylene homo and/or copolymerizate as a bottom by means of thermo-laminating, welding, sewing or stitchbonding.
The thermolaminating should be performed by melting the surface of the foamed sheeting and pressing-on of the upper layer, doing so the pressing-on can both be done continuously by means of a roller system and discontinuously by means of a press. The textile surface layer should preferably be preheated.
The welding of the thermoplastic foamed sheeting on the textile layer can be performed by spot welding or by linear welding. In case that several lengths of foamed sheetings have to be applied as a bottom to a wider textile layer, the lengths of foamed sheetings should preferably be connected by means of welding, sewing or a hot sealing band.
In applying the foamed sheeting it is possible to connect simultaneously or afterwards additional sheetings, e.g. metal sheetings, non-foamed plastic sheetings, should this be necessary for special fields of application. In order to preserve the foam structure the bottom side should be cooled while the surface of the foamed material is melted.
It is also possible to connect a textile surface layer, which has not been pretreated with a plastic dispersion, with the bottom of thermoplastic foam by means of a non-porous elastic thermoplastic layer, into which the carrier layer has been incorporated, the bottom of thermoplastic foam having a density drop.
The density drop in the bottom of thermoplastic foam is in the range of 0.1 to 0.4 g/cm.sup.3 at the bottom side and up to 0.5 to 0.9 g/cm.sup.3 at the densified upper side, which forms a non-porous elastic layer, a so-called rind. The thickness of this layer is 10 to 50 percent of the total thickness of the bottom.
This textile floor covering is manufactured in such a way that a surface layer of the sheeting of thermoplastic foam, having a thickness of 0.3 to 3 mm, is melted and the textile layer, having not been pretreated with a plastic dispersion, is pressed on the thermoplastic melt with a pressure of 5 to 30 ats. In order to preserve the foam structure the bottom side should be cooled while melting the surface of the foamed material.
The essential merit of this process is the fact that the textile layer need not be pretreated or densified by naps by means of a plastic dispersion. Due to the incorporation of the carrier layer of the textile material into the thermoplastic according to the invention a high strength of the textile layer is achieved without any previous finish.
The density-drop in the bottom of thermoplastic foam and the non-porous elastic thermoplastic layer at the bonding line between the textile and plastic materials resulting therefrom, produces an excellent step elasticity, a high mechanical strength of the covering, a good restoring property as well as dust and water impermeability. This process is characterized by its easy practicability as well as by the small number of technological process steps.
The manufacture of the textile floor covering can also be performed in such a way that a melt of a polymerizate or copolymerizate of ethylene is applied to the surface of the foamed sheeting and that this sheeting is combined with the bottom side of the textile layer. Doing so the textile layer should be preheated. The same can also be done with the surface of the foamed sheeting. The two layers can be combined by means of rolls or presses.
Using this process there is the advantage that the thickness of the foamed sheeting will not be affected by melting and that, nevertheless, there will be a good and direct bond between the two layers due to the identity or affinity of the chemical structure of the two plastic materials.
All waste matter of the ethylene polymerizate, especially the waste matter from the manufacture of the foamed sheeting proper, which can also contain mechanical contaminations, can be used as a melting component. This fact results in a special economic advantage. Furthermore, non-identical ethylene-vinylacetate copolymerizates with the most different melt indices can be used.
Using this invention the following merits will result: The production speed in applying the bottom of plastic foam will increase upto 5 to 18 m/min, preferably 10 to 15 m/min, compared with 3 m/min with the application and foaming of caoutchouc-latex mixtures. The energy consumption, being considerably high for the removal of the water from the latex, will also be reduced.
The thermolining of the bottom can be done on technically simple machines, and several operations can be saved in the carpet industry. At the same time the chemical-specific procedure is removed from this line of industry, the control of which is in many cases insufficient. By the separate manufacture of the foamed sheeting the foam properties can be specifically influenced, which improves the properties of the finished product.
Using the foamed sheetings of ethylene-polymerizate a new raw material for the carpet industry is developed having better properties than the foams used hitherto. Due to the cellular structure there is practically no water absorption. Polyethylene foam ages much less than PVC foam or caoutchouc-latex foam. It possesses good strengths and a better pressure elastic behavior.
Using 100 percent synthetic carpet bottoms the product according to the invention is resistant to rotting and can, therefore, be used in the open air, in moist rooms and in motor vehicles. In addition it is thermoworkable. Therefore, it is possible to manufacture formed floor coverings to be used in vehicles, cabins and other rooms with uneven floors.